Peocess foe hunting with vat dyestuffs



g Patented Jan. 21, 1930 UNITED STATES PATENT OFFICE ERNST .PFEFFER, OF FBANKFORT-ON-THE-MAIN-SCHWAHNHEIM, GERMANY, AS SIGNOB TO GENERAL ANILINE WORKS, INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE No Drawing. Application filed The present invention relates to a process for printing with vat dyestuffs. In my co-pending U. S. Patent application Serial No. 226,521 filed on October 15, 1927, a process is described which consists in printing the material with a vat dyestu'fi mixed with a solution of a cellulose ester or a cellulose ether, i. e. an organo-oxy derivative of cellulose, subsequently treating the printed 4 material with-a reducing agent and an alkali, then drying it and finally developing the dyestuff in a rapid steam-ager (Mather-Flatt). I have now found that the process of my said U. S. Patentapplication mayconsi'der-- ably be simplified'by passing for a short time ,the material after: being printed through an alkaline bath. to which, instead of rongalite C (formaldehyde-sulfoxylate), hydrosulfite and advantageously a wettingagent has been added. By treating the printed material with an alkaline hydrosulfite solution the cellulose ester or cellulose ether, i. e. an organo-oxy derivative of cellulose, which is insoluble in alkali and used as thickening agent, is precipi- 5 tated. Any bleeding of the dyestufi is thereby prevented even if the material is further treated in a wet state. Therefore it is nolonger necessary to dry the material before steaming it; furthermore steaming may be operated in a roller box, and that in a shorter time, because hydrosulfite does not require first to be split in contrast to rongalit'e C.

The new process is distinguished by the great economy it afi'ords'as intermediate-drying operation may be abolished and furthermore short steaming in an ordinary ro instead of in a rapid steam-ager (Mather- P latt) is quite suflicient and a hydrosulfite may be used instead of formaldehyde-sulfoxylate. The following examplesgserve to illustrate my invention but they are-not intended to limit it thereto.

The material is printed withthe following printing color:

Printing color ofthe black vat d estufi' prepared according to erman Patent No. 241,997 in the form of a paste 200 grams ller box,

PROCESS FOR PRINTING- VAT DYESTUFFS January, 1929, Serial No. 334,363, and in Germany January 26, 1928.

700 grams of thickening M 100 grams of water 1000 grams.

Thickening M f p 100 grams of methylcellulose are dissolved 1 11 900 grams of cold water 1000 grams. I

After the material has been printed it is padded with the following solution:

100 grams of hydrosulfit concentrated po der . l 730 grams of water 150 com. of caustic soda solution of 40 B.

l5---grams of sodium salt of the benzyl-sulfanilic acid 5 grams of a wetting agent 1 liter.

and then immediately steaming in a roller box for half a minute. The material is then washed and soaped at the boil.

'If to the alkaline quantity of a vat dycstufl' is added a groundcolorlng operation may be carried out simul- 3 grams'of N-dihydro-1.2-1'.2'anthraquinone-azme 722 grams of water 15 ccm. of caustic soda solution of 40 B.

15 grams of the sodium salt of the benzylsulfanilic acid 5 grams of a wetting agent 100 grams of hydrosulfite concentrated powder, the whole being made up to 1 liter.

hydrosulfite bath a small In the following claims the term organooxy derivative of cellulose is to be understood to comprise ethers and esters of cellulose.

' .I claim:

1. The process for printing with vatdyestufis, which comprises printing the material with a vat dyestufi' mixed with a solution of an organo-oxy derivative of cellulose, subsequently treating the material with an aqueous solution of hydrosulfite and an alkali, and immediately developing the (lyestuf'f by steaming it.

2;" The process for printing with vat dyestuffs, which comprises printing the material with a vatdyestufi mixed with a solution of a cellulose ether, subsequently treating the material with an aqueous solution of hydrosulfite and an alkali andimmediately developing the dyestufi by steaming it.

' 3. The process for printing with vat dye stufi's, which comprises printing the material with a "at dyestufi' mixed with an aqueous so-- lution of a cellulose ether, subsequently treating the. material with an aqueous solution of hydrosulfite and an alkali and immediately developing the dyestufi' by steaming it.

4. The process for printing with vat dyestuffs, which comprises printing the material so with a vatdyestutf mixed with an aqueous solution of methyl cellulose, subsequently treating the material with an aqueous solution of hydrosulfite and an alkali and immediately developing the dyest1 ifi by steaming it.

In testimony whereof, I afiix my signature.

I :ERNST PF EF FER. 

